Two-photon microscopy allows for the visualization of cellular processes, such as cell[unreadable] migration, cell-to-cell and cell-to-matrix interactions, subcellular organelle function[unreadable] (mitochondria), cellular signaling (Ca2+, reactive oxygen species, and phospholipid[unreadable] uptake), characterization of tumor growth, drug targeting, and protein expression within[unreadable] the three-dimensional, natural environment of intact organs in living animals. During the[unreadable] past few years, two-photon microscopy has revolutionized our view of developmental,[unreadable] homeostatic, and pathologic processes. We propose to establish an intravital two-photon[unreadable] microscopy system at The Institute for Environmental Medicine (IFEM) through the[unreadable] acquisition of a Leica TCS SP5 Spectral Confocal and Two-Photon Microscope in[unreadable] combination with a Spectra-Physics Broadband Mai-Tai femtosecond-pulsed Laser. The[unreadable] major users of the proposed instrument will be a group of School of Medicine[unreadable] Investigators drawn from a wide range of disciplines, including Physiology, Pathology,[unreadable] Emergency Medicine, Pulmonary Medicine, Cancer Biology, Rheumatology,[unreadable] Hematology/Oncology and Immunology research. The need to translate experimental[unreadable] data from culture models into living animals, and to expand static information of dynamic[unreadable] cellular processes into four- dimensional kinetic analyses in vivo has greatly augmented[unreadable] the need for intra-vital imaging at the IFEM. Such research cannot be conducted by[unreadable] equipment currently available. Promising preliminary studies documenting ROS[unreadable] production in the lung, vascular targeting of nanocarriers, trafficking of T-cell progenitors[unreadable] in vivo, and immune cell interactions during inflammatory and infectious diseases has[unreadable] demonstrated the feasibility of two-photon microscopy for the proposed projects. The[unreadable] instrument will be centrally located in the School of Medicine to enable convenient[unreadable] access for all users, will be maintained by the IFEM under the supervision of the PI and[unreadable] Microscope Advisory Committee. Investigators from diverse fields will have new[unreadable] opportunities for interaction and the initiation of interdisciplinary research projects, which[unreadable] will significantly advance their NIH-funded projects. It is anticipated that the instrument[unreadable] will help to obtain novel insights into the normal cellular physiology, drug delivery, and[unreadable] various pathologies involved with aging, cancer, acute lung injury, transplantation,[unreadable] pulmonary hypertension, atherosclerosis, autoimmunity, and chronic infections.[unreadable] Relevance: The purpose of the 2-Photon microscope is to facilitate increased interaction[unreadable] among clinical investigators and basic scientists who are dedicated towards the study of[unreadable] various disease models and their possible treatment. This instrument will be invaluable[unreadable] in translating in vitro cell culture studies to intact organ or live animal. Overall, the[unreadable] equipment will enhance and expand IFEM Core to provide state of the art support to the[unreadable] School of Medicine at Penn.